10 ECU

The ECU (European Currency Unit) was never legal tender in the conventional sense — it existed as a basket currency, a weighted composite of EEC member currencies used for accounting and settlement within the European Monetary System. Greece's participation in producing collector ECU issues during the early 1990s reflected its formal EMS membership, though the drachma itself remained volatile and Greece would not qualify for euro adoption until 2001, years after other founding members.

These silver collector ECUs were issued by national mints across member states under a loose framework; they circulated nowhere and settled nothing. The series ended with the euro's physical introduction in 2002.